- It's not that important when we have the sbws version stated nearby
- It *really* means last built, and that isn't generally useful to know.
  For example, the onion service is updated every hour (or something).
  So it always says today or yesterday

Can be overridden by --output option to sbws generate

GH: closes #91

 Conflicts:
	sbws/core/generate.py

GH: closes #127

Make executive decision that sbws.bin is better filename than the proposed
name 1G in the ticket. We can duke it out later if desired.

GH: closes #123

GH: closes #67

- Also do some switching away from time_now() back to time.time()
GH: ref #67

- Add note in CONTRIBUTING to prefer UTC and timestamps

- Fix things that broke when switching from date to datetime.

GH: closes #113

This allows people to run 'tox' without arguments on machines that don't
have all our target python versions installed.

GH: closes #115